Inflatable boats, such as those used as tenders and life rafts, have been on the market since the late 1930's. These boats have the advantage of being light weight, mobile and collapsible, making them convenient to carry along, especially for use as emergency vessels. Inflatable boats may include an inflatable keel covered by a rigid or semi-rigid floor, or they may just include a flexible floor.
Inflatable boats have the disadvantage of being flexible, making them difficult to lift, especially using a four-point lifting system or when carrying a load. Therefore, although launching of the inflatable boats is efficient and convenient, recovery of these boats back to a ship or other transport system after use is difficult and sometime impossible. Flexibility also results in inefficient use of fuel, as the boat bends with the waves instead of moving over the waves, making their usable distance on a fixed amount of fuel very limited. In addition, conventional materials for constructing inflatable boats tend to be highly vulnerable to ultra-violet radiation and solvents, easily abradable and limited in shelf life due to breakdown of the material over time. Other disadvantages of inflatable boats include the inability to effectively carry gear within the boat or to mount gear on the boat.
Rigid inflatable boats, also known as RIBs, typically have a rigid hull constructed of fiberglass or aluminum, surrounded by and connected to an inflatable sponson or tube. The hull is usually designed as a planing hull allowing the boat to effectively ride over the waves, thereby increasing the fuel efficiency, stability and seaworthiness of the boat. RIBs are currently available for commercial, safety, rescue, diving and leisure activities. They can include inboard or outboard motors, or can be jet powered. RIBs can have open decks, driving consoles, and wheel-houses or cabins, depending on the size of the boat and the needs of the boater.
Although RIBs are more stable and durable than inflatable boats, they are heavier and less compact, requiring more storage and transport space. In addition, although RIBs are available in numerous different sizes and styles to meet many different boating applications, once a RIB is purchased for a specific application its configuration is set by that application. Only minor changes to the boat's configuration are generally possible after the boat has been fabricated, such as moving seats, changing the outboard motor, or relocating gear within the boat. Other drawbacks to standard RIBs include the use of fiberglass hulls to achieve reasonable boat weights, the use of rigid hull bottoms without rigid sidewalls in many instances to reduce weight, and non-portability due to overall size and weight of the RIB and its components.
To meet current needs within the boating community, especially in the military, rescue and safety areas, a light weight, adaptable rigid hulled boat is needed. Such boat should also be small enough for transport by search and rescue transportation, such as helicopters, boats and other vehicles.